Study On Processing Technology Of Ready-to-eat Sea Cucumber

Sea cucumber (Holothurian) is a kind of rare marine animal, and honored as one of "eight treasures" seafoods. It is considered as the ginseng in the sea, due to the rich nutrients and the high medicinal properties. In China, sea cucumber aquaculture is developing rapidly in recent years. In China the yearly output of sea cucumber reached to 130,000 tons in 2010, an increase of 27.55% over 2009. As one of the main sea cucumber cultivating provinces in China, the output of sea cucumber in Fujian reached to 1,643 tons in 2010. However, the main form of sea cucumber product is dried sea cucumber, which has seriously hampered the development of sea cucumber based-processing industry. Therefore, the best rehydration conditions of dried sea cucumber are researched in this paper with the dried sea cucumber(Stichopus japonicas) as raw material. The best processing method is determined by the comparison of the different organizational structure of sea cucumber by scanning electron microscopy (SEM) under different processing conditions. The hurdle factors are studied to inhibit the growth of microorganisms in read-to-eat sea cucumber products. The major spoilage bacteria of read-to-eat sea cucumber after sterilization were detected, and effective measures to suppress the growth of microorganisms of the read-to-eat sea cucumber were taken to extend its shelf life. The main results are as follows:(1)The major components of dried sea cucumber were studied and the results show that the moisture content:19.89±0.25%, protein content:48.65±0.12%, fat content: 4.66±0.08%, ash content:21.97±0.18%, others:4.84±0.20%. It concludes that the dried sea cucumber is a kind of seafood with content of high protein but low fat.(2) Rehydration conditions of dried sea cucumber were optimized by orthogonal test with the rehydration rate, hardness, elasticity and protein content in rehydration solution as indicators. The results show that the best rehydration conditions of dried sea cucumber are: blanching temperature:85℃, blanching time:10 min, insulation rehydration temperature: 70℃, insulation rehydration time:40-50 h, and rehydration ratio:5-6. The dried sea cucumber rehydrated under these conditions has a best texture and taste which shows it would be an ideal method that can provide theoretical basis for dried sea cucumbers.(3) The comparison of the organizational structure after rehydrated by scanning electron microscopy (SEM) of the dried sea cucumbers, read-to-eat sea cucumber with mild processing and canned sea cucumbers with high temperature and high press sterilization shows that the read-to-eat sea cucumber with mild processing is an ideal processing method. Seasoning recipe for read-to-eat sea cucumber was optimized by orthogonal.The results show that the best seasoning recipes for read-to-eat sea cucumber are:salt content:1.5%, sugar content:4.0%, and MSG content:2.0%.(4) The optimum water activity of read-to-eat sea cucumber is 0.91±0.01 through the single factor test with hardness, elasticity, sensory scores and total number of colonies as index. With the total number of colonies as an indicator, optimal parameters acetate dosage, sterilization temperature and sterilization time were obtained using two routable central composite design based on the single factor experiment. The results show that the optimum parameters for the read-to-eat sea cucumber fence factors are:Aw:0.91±0.01, acetic acid: 5.6%(pH=5.0-5.4), sterilization temperature:95℃ and sterilization time:35 min.(5) The main spoilage bacteria in read-to-eat sea cucumbers after sterilization at room temperature were analyzed with PCR technology. The results show that the main spoilage bacteria are Lactococcus and Bacillus subtilis after sterilization in read-to-eat sea cucumber.(6) The effect of different packaging on the sensory score and total number of colonies during the storage of read-to-eat sea cucumber were researched. It shows that the vacuum packaging is the best way for the read-to-eat sea cucumber. Meanwhile, the effects of different preservatives on inhabitation of microorganism of read-to-eat sea cucumber were studied. Lysozyme, Nisin and sodium lactate were selected as best antiseptic for read-to-eat sea cucumber, and the inhibition rates are:27.72%,22.43% and 16.17% respectively. Preservatives composition was optimized as well:lysozyme dosage:6%o, Nisin dosage:6‰ and lactate dosage:4%o. Inhibition rate of read-to-eat sea cucumber is 53.16% under these conditions.